Personal computers? Yes. At 260 West Broadway in New York City simple computers come for the first time as a standard option for a US home. If you don't want the computer, you can exchange it for a $700 refund.

In 1981, about 25 percent of the 700,000 to 800,000 personal computers sold were bought just for home applications. By 1990, between 9 and 10 million personal computer systems will be on the market - and about half of those will end up in the home. So says a study conducted last August by California's Stanford Research Institute International (SRI). Even so, Esmond Lyons, director of the computer industries department at the institute, says the 1990 penetration will ''not be much . . . only 10 to 15 percent of American households.''

There is no questioning the usefulness of personal computers for business. Who can argue about a computer that spares your accountant, bookkeeper, secretary, stockbroker, and marketing and sales managers hours of drudgery?

But shadows of doubt lurk when you talk about the computer at home. Is it really worth spending $400 to $1,500 for a computer just to file your recipes and balance your checkbook?

''Right now there seems to be very little 'usefulness' (to computers used strictly for home applications),'' SRI's Mr. Lyons notes. ''They're more gadgetry than anything else.''

This, though, is just one side of the story. Many computer enthusiasts, hobbyists, and home users rave about their machines. And, of course, so do the manufacturers.''It is an information organizer, a valuable tool to help in daily life,'' says Phillip Estridge, vice-president of IBM's system products division.

So it comes down to this: What exactly can be done with a personal computer at home?

Right now, depending on the kind you buy, the peripherals - or ''extras'' - you buy for it, and the software (the program instructions that tell your computer how to solve a problem or draw a picture), you can still do a lot. The uses cover the broad areas of family finances, education, and entertainment. At the moment, video games are still the most popular use for home computers. SRI says software programs that drill your children in various subjects are a close second.

Sherry Jenkins Martin, from Weston, Mass., bought an Apple II last June. A journalist, real estate broker, and mother, she finds endless uses for her Apple. She's also just plain ''fascinated'' with computers.

Mrs. Martin's computer helps her in fundamental ways. She uses the popular VisiCalc software program (an electronic budget sheet that changes totals automatically when you change one variable) to help with bookkeeping in the real estate business. She also uses a text editing program when she reports on local town meetings.

Even with these uses, home computers have a way to go before they'll be considered worth the cost for the average homeowner.

''The proliferation of home computers is greatly dependent on the availability (and cost) of data banks, especially more specialized ones, and the growth of networking,'' says Mr. Lyons at SRI.

Data banks and networking are two words in the vocabulary of computer jargon. Data banks are computers with large memories full of information and available to you and your computer through a telephone hookup. Networking is simply talking (typing, really) to other computer users through your mutual hookup with the data bank.

Two data banks are already quite successful: CompuServe (800-848-8990) and the Source (800-336-3366). They are practically neck and neck in services offered. Both say electronic mail -- sending letters to other data bank users by computer -- is their most popular service.

Nancy Beckman, a spokeswoman for the Source, says it now has 17,000 members and is adding 1,200 to 1,400 a month. A smattering of the 800 subject areas offered by the Source include: electronic shopping; a travel club, a nationwide restaurant guide; and a networking service called Chat.

With a membership of 23,000, CompuServe offers many of the above. It has some nice touches - a car-care clinic with advice from Popular Science magazine's car expert; history trivia quizzes; banking through the United American Bank; and 11 newspapers. Both services charge you for the amount of time you spend using them.

Once you know how to get around in a data bank, it's a lot less expensive to simply copy its files onto your computer and read them later.

There are certain factors working against the homeowner. If you're not like Mrs. Martin and you don't run a business from home, they become especially important.

First is cost. If you want large memory capabilities and room to expand your system, you are talking about Apples, IBMs, and $1,500 for a basic system. Add printers, disk drives, maximum memory capacity, phone hookups (modems), game controls (joy sticks), and you can easily shoot the price up to $5,000.

But there are some good computers in the $150-to-$400 range. The May issue of Popular Computing gives an excellent rundown on four of these: the Atari 400; Radio Shack's TRS-80 Color Computer; the Sinclair ZX81; and the Commodore Vic-20 . They all use a TV set as the video screen and have limited memory capabilities.

Also remember that every time you choose a new software package it will cost you. Many simple packages cost $15 to $25 (games and some education programs); more complicated ones range from $100 to $200 (this includes VisiCalc and income tax programs).

''The home market is pretty elastic in respect to price,'' says Elias Blawie, manager of microcomputer services at Creative Strategies International, a California research group that keeps close tabs on personal computers. ''The home market will not pay the $150 to $200 and up for programs now being paid in the business world,'' he says.

Sherry Martin talks about the problems she has come up against as a user. All software programs come with an instruction manual. ''Manuals are awful,'' she says. ''The biggest, most successful, most powerful word-processing program is called WordStar. . . . But you can't learn it unless you have someone leaning over your desk telling you how.''

A related problem is program support. Companies that make large computers, such as Wang and Digital Equipment, ''support'' their systems by visiting users when bugs in the software show up. But Mrs. Martin says if you have a wrinkle in your personal computer program, it's difficult to find the person who wrote it to straighten it out.

Finally, she believes, computer technology still scares people. She says there is an answer for this in ''user groups.'' User groups have members who get together and discuss computer programs and machinery and often set up workshops for beginners. Any Computerland, Radio Shack, or other computer retail store should have ''user'' information.

Despite the above obstacles, Mrs. Martin believes that ''very shortly computers will become as important to anyone's kitchen as a toaster.'' She is not talking about fancy computers with large memory or even computers with printers. A simple computer with a phone hookup will be all you need to scan through a grocery store ''menu,'' pick out your weekly supply, charge it, and have it delivered, she claims.